Astronomy Chpt 21, Stellar Explosions

fission of heavy nuclei back toward lighter ones
Beyond the formation of iron, nuclear energy can be produced only by

neutronization
As a star evolves, heavier elements tend to form by various processes. Which of the following is not one of these processes?

true
Because they all involve the detonation of a carbon-rich white dwarf at Chandrasekhar’s limit, all type I supernovae are equally luminous.

1.4 solar masses
The Chandrasekhar mass limit is

All of the above are correct
What made supernova 1987a so useful to study?

oxygen 16
When helium capture occurs with a carbon 12 nucleus, what results?

All of the above are correct
As a star’s evolution approaches the Type II supernova, we find

mass-transfer binary
For a nova to occur, the system must have already been a

a Type II supernova
Which of these does not depend on a close binary system to occur?

rich in hydrogen from the outer envelope of the collapsed star.
Type I supernovae are NOT

by neutron capture during a type II supernova explosion.
The heaviest nuclei of all are formed

Type I supernova
A recurrent nova could eventually build up to a

day
A 20 solar mass star will stay on the main sequence for 10 million years, yet its iron core can exist for only a

a mass-transfer binary, with the white dwarf already at 1.3 solar masses
Which of these is the likely progenitor of a type I supernova?

true
The spectra of the youngest stars shows the most heavy elements present

even numbered elements
The alpha process tends to produce chiefly

white dwarfs and companion stars producing recurrent Type I supernova events
Which of these events is not possible?

neutrino
In neutronization of the core, a proton and an electron make a neutron and a

1.4 solar masses, the Chandrasekhar Limit.
For a white dwarf to explode entirely as a Type I supernova, it’s mass must be

All of the above are evidence of this
What direct evidence do astronomers have that supports the heavy element formation in stars?

neutrinos
Most of the energy of the supernova is carried outward via a flood of

hydrogen and helium
Nearly all the elements found in nature were formed inside stars, except for

nova
A surface explosion on a white dwarf, caused by falling matter from the atmosphere of its binary companion, creates what kind of object?

an evolved red giant which is just starting to make silicon in its core
Which of these is the likely progenitor of a type II supernova?